I finished playing Mercenaries 2 for Xbox360 a couple days ago.  It was a fun game but not challenging and the storyline was short and non-engaging.  The side quests and my own personal quest for acheivement points is what really kept me playing for the 40+ hour I logged on the game over the course of a month, but other than large explosions and learning all about the landscape and geography of Venezuala the game was pretty boring.